JP6609484B2 - In-vehicle display device - Google Patents

Description

  The present invention relates to an in-vehicle display device in which a virtual image formed in front of a projection member such as a windshield glass can be viewed from the rear of the projection member, and in particular, at a position at a different distance in front of the projection member. The present invention relates to a mounting display device on which a plurality of virtual images are formed.

  Patent Document 1 describes an invention related to an information display device used as a head-up display.

  In this information display device, two transmissive screens are arranged in front of a video projector, and information is imaged on each screen by the video projector. The distances from the respective screens to the image forming member that is the windshield glass are different. The image formed on each screen by the image forming member is reflected by the image forming member and directed to the viewer. As a result, a virtual image formed in front of the image forming member is visually recognized by the viewer.

  Since the distance between each screen and the image forming member is different, an image formed on the screen at a position distant from the image forming member is a virtual image at a position distant from the image forming member. A virtual image is formed at a position near the front of the image forming member by the image formed on the screen at a position close to the image forming member.

  In this way, the viewer who is the driver can observe the respective virtual images formed at different positions in front of the image forming member that is the windshield glass.

JP2015-34919A

  The information display device described in Patent Document 1 forms virtual images at different positions in front of the image forming member by differentiating the distance between the two screens and the image forming member.

  Here, a video projector structured to scan display light using a MEMS mirror or the like can theoretically form an image on the screen even if the distance between the video projector and the screen is changed. It is. However, in practice, when the distance between the video projector and the screen changes, defocusing occurs and the image tends to be blurred. In particular, blurring becomes prominent in the peripheral portion of an image where the opening angle increases when the MEMS mirror is scanned. In the information display device described in Patent Document 1, since the distances between the respective screens and the image forming member are different from each other, out-of-focus is generated in any of a plurality of virtual images formed in front of the image forming member It's easy to do.

  In the information display device described in Patent Document 1, a variable focus lens and a projection lens are used to correct a difference in distance between the video projector and the screen. However, providing such a lens increases the cost of the apparatus. Further, since the transmissive lens has chromatic aberration, there is a possibility that color shift may occur due to chromatic aberration when display light having a plurality of hues is used. This color misregistration is likely to appear remarkably in the outer peripheral portion of the image.

  The present invention solves the above-described conventional problems, and forms a virtual image at a position where the distance in front of the projection member is different by varying the distance between the transmission type screen and the projection member such as windshield glass. Another object of the present invention is to provide a vehicle-mounted display device that employs a structure in which image blur and color shift due to chromatic aberration do not easily occur due to defocus.

The present invention includes a first transmission screen and a second transmission screen, an image forming unit that forms an intermediate image on each of the transmission screens, and a projection unit that projects the intermediate image on a projection member. In the in-vehicle display device in which the virtual image in front of the projection member can be viewed from behind the projection member,
The intermediate image is formed on both the first transmission screen and the second transmission screen in the common image forming unit,
The optical path from the first transmissive screen to the projection member is longer than the optical path from the second transmissive screen to the projection member,
The optical path from the image forming unit to the first transmissive screen and the optical path from the image forming unit to the second transmissive screen are substantially the same length,
The optical path from the image forming unit through the first transmission type screen to the half mirror is set to be longer than the optical path from the image forming unit through the second transmission type screen to the half mirror,
Virtual image based on the intermediate image formed on the first transmissive screen, characterized in that located is away from said projection member than the virtual image based on the intermediate image formed on the second transmissive screen Is.

The in-vehicle display device of the present invention includes a first reflecting mirror disposed on an optical path from the image forming unit to the first transmissive screen, and from the image forming unit to the second transmissive screen. A second reflecting mirror disposed on the optical path,
The first reflection mirror and the second reflection mirror may be configured to face the image forming unit in different regions within an image forming range formed by the image forming unit.

  In the in-vehicle display device of the present invention, the image forming unit is provided with a scanning mechanism that scans display light, and the first reflection mirror is scanned when the display light is scanning the first reflection mirror. An intermediate image is formed on the transmissive screen, and an intermediate image is formed on the second transmissive screen when the display light scans the second reflecting mirror.

  The in-vehicle display device according to the present invention includes a reflection mirror located on an optical path from the image forming unit to the first transmissive screen, and an optical path from the image forming unit to the second transmissive screen. It is preferable that at least a part of the reflecting mirror is a concave mirror.

  The in-vehicle display device of the present invention makes the first transmission by making the optical path from the first transmission type screen to the projection member longer than the optical path from the second transmission type screen to the projection member such as a windshield. The virtual image formed by the mold screen can be formed at a position farther forward from the projection member than the virtual image formed by the second transmission screen.

  However, the optical path from the image forming unit to the projection member through the first transmission type screen is set to be longer than the optical path from the image formation unit through the second transmission type screen to the projection member. The difference between the optical path from the forming section to the first transmissive screen and the optical path from the image forming section to the second transmissive screen can be reduced, and preferably both optical paths can have substantially the same length.

  As a result, the defocus of the virtual image formed by the first transmissive screen and the virtual image formed by the second transmissive screen can be eliminated, and the occurrence of image blur can be prevented.

  Also, a first reflecting mirror disposed on the optical path from the image forming unit to the first transmissive screen, and a second reflecting mirror disposed on the optical path from the image forming unit to the second transmissive screen. Are opposed to the image forming unit in different regions within the image forming range formed by the image forming unit, so that a plurality of virtual images can be formed by one image forming unit. In particular, by causing the display light to scan the first reflection mirror and the second reflection mirror, different virtual images can be formed by one image forming unit.

  In addition, the use of a concave mirror as the reflection mirror can prevent the occurrence of chromatic aberration.

Explanatory drawing which shows the state by which the vehicle-mounted display apparatus of embodiment of this invention is mounted in the vehicle, The perspective view which shows the projection operation | movement of the vehicle-mounted display apparatus of embodiment of this invention, The perspective view which shows arrangement | positioning of the main components of the vehicle-mounted display apparatus of embodiment of this invention, The side view which shows arrangement | positioning of the main components of the vehicle-mounted display apparatus of embodiment of this invention, (A) (B) is explanatory drawing of a reflective mirror, FIG. 4 is a view taken along the line VI-VI in FIG. 4 showing the positional relationship between the image forming range A formed by the image forming unit, the first reflecting mirror, and the second reflecting mirror;

  FIG. 1 shows a vehicle-mounted display device 10 according to an embodiment of the present invention mounted on an automobile 1 which is an example of a vehicle.

  In the automobile 1, a windshield glass 4 is mounted between the bonnet portion 2 and the ceiling portion 3, and the vehicle compartment space 5 and the external space 6 in front of the vehicle are partitioned by the windshield glass 4. . The windshield glass 4 is curved, the concave surface of the windshield glass 4 is directed to the passenger compartment space 5, and the convex surface of the windshield glass 4 is directed to the front external space 6. The windshield glass 4 functions as a projection member or a half mirror having a concave curved surface.

  However, in the present invention, the windshield glass 4 does not function as a projection member, and a curved projection member called a combiner may be separately disposed on the vehicle interior side of the windshield glass 4.

  A driver's seat 7 is provided in the passenger compartment space 5, and a steering wheel 8 is provided in front thereof. A dashboard 9 is provided in front of the passenger compartment space 5, and the in-vehicle display device 10 according to the embodiment of the present invention is embedded in the dashboard 9. The on-vehicle display device 10 is a so-called head-up display (HUD) device.

  FIG. 2 shows a part of the in-vehicle display device 10 and the windshield glass 4. 3 and 4 show the components of the in-vehicle display device 10 in more detail. FIG. 3 is a perspective view showing components of the in-vehicle display device 10, and FIG. 4 is a side view of the components shown in FIG. 3 as viewed from the direction of the arrow IV.

  As shown in FIGS. 3 and 4, the in-vehicle display device 10 is provided with an image forming unit 11. The image forming unit 11 has a MEMS mirror and a light source. The MEMS mirror has a MEMS (Micro Electro Mechanical Systems) configuration, and includes a movable mirror and a scanning mechanism that rotates the movable mirror in the X direction and the Y direction. In addition, a light source that emits visible light laser of R (red) as display light and a light source that emits visible light lasers of G (green) and B (blue) are provided. The light sources that emit the lasers of the respective colors are switched by a switching element to operate.

  Further, a known DLP (Digital Light Processing) projector may be used as the image forming unit 11.

  A first reflection mirror 12 and a second reflection mirror 13 are arranged on the Z1 side (the vehicle compartment space 5 side) from the image forming unit 11. The first reflection mirror 12 and the second reflection mirror 13 are plane mirrors. The first reflecting mirror 12 is located farther from the image forming unit 11 than the second reflecting mirror 13.

  As shown in FIG. 4, the first reflection mirror 12 is located above the second reflection mirror 13 in the Y direction. FIG. 6 is a view taken in the direction of arrows VI-VI in FIG. 4 and viewing the first reflection mirror 12 and the second reflection mirror 13 from the image forming unit 11 side. As shown in FIG. 6, when the Z1 direction is viewed from the image forming unit 11 side, the first reflection mirror 12 is located on the upper side, and the second reflection mirror 13 is located on the lower side. The mirrors 12 and 13 overlap each other by a slight dimension δ in the vertical direction.

  In FIG. 6, an image forming range A formed by the image forming unit 11 is surrounded by a chain line. The image forming unit 11 irradiates display light (display beam) L such as a visible light laser in the Z1 direction within the image forming range A, scans the display light L in one row in the X direction, and scans the scanning row H in the Y direction. A projection operation is performed to move little by little. As shown in FIG. 6, the reflection surface of the first reflection mirror 12 and the reflection surface of the second reflection mirror 13 are opposed to the image forming unit 11 in different regions separated vertically in the image forming range A. .

  Therefore, in the upper region in the image forming range A, the scanning light S1 obtained by scanning the display light L with the movable mirror is not reflected by the second reflecting mirror 13, but reaches the first reflecting mirror 12 and faces upward. Reflected. In the lower region within the image forming range A, the scanning light S 2 scanned with the display light L is reflected upward by the second reflecting mirror 13 and does not reach the first reflecting mirror 12.

  2, 3, and 4, the scanning light S <b> 1 in the upper region is indicated by a solid line, and the scanning light S <b> 2 in the lower region is indicated by a broken line.

  As shown in FIGS. 3 and 4, the scanning light S1 reflected by the first reflecting mirror 12 is reflected by the third reflecting mirror 14 positioned on the scanning light S1 and directed forward (Z2 direction). The scanning light S2 reflected by the second reflecting mirror 13 is reflected by the fourth reflecting mirror 15 located on the scanning light S2 and sent forward (Z2 direction).

The third reflection mirror 14 will be further described based on FIGS.
FIG. 5A shows a problem when the flat mirror 14a is arranged as the third reflecting mirror. Since the image forming unit 11 reflects the display light L with the movable mirror and rotates the movable mirror in the X direction and the Y direction with the scanning mechanism to generate an image with the scanning light S1, the scanning light S1 scans. As the distance from the center of the range increases, the incident opening angle α of the scanning light S1 to the flat mirror 14a increases, and the reflection angle β of the scanning light S1 reflected by the flat mirror 14a, that is, a first transmission screen 16 described later. The incident angle of the scanning light S1 on the screen also increases. As a result, the display image is likely to be blurred or uneven in brightness as it goes toward the edge of the display area.

  Conventionally, by arranging a field lens in one of the optical paths from the image forming unit 11 to the windshield glass 4 (projection member) and adjusting the incident opening angle β, occurrence of blurring of images and uneven brightness are suppressed. doing.

  However, using a field lens increases the manufacturing cost because it increases the number of relatively expensive optical components. Furthermore, since the field lens has chromatic aberration due to a change in refractive index due to a difference in light wavelength, problems such as color misregistration of a display image are likely to occur.

  Therefore, in the in-vehicle display device 10 according to the embodiment, as shown in FIG. 5B, the third reflection mirror 14 is a concave mirror, so that the scanning light S1 at a position away from the center of the scanning range. The opening angle in the reflection direction is reduced. In other words, the third reflection mirror 14 is set to have the same light correction function as that of the field lens, so that the reflection mirror 14 can perform the same light correction as that of the field lens. Further, since the concave mirror does not have chromatic aberration like a lens, it is possible to prevent a color shift of a display image.

  The same applies to the fourth reflection mirror 15, and the fourth reflection mirror 15 is also preferably a concave mirror. That is, it is preferable that at least one of the two reflecting mirrors 14 and 15 is a concave mirror.

  As shown in FIGS. 3 and 4, the first transmission type screen 16 is disposed in front of the reflection direction of the third reflection mirror 14, and the second transmission type is provided in front of the reflection direction of the fourth reflection mirror 15. A screen 17 is arranged. Of the scanning light formed by scanning the display light L in the image forming unit 11, the scanning light S <b> 1 indicated by the solid line that scans the region above the image forming range A is the first reflecting mirror 12 and the third light. A first intermediate image is formed on the first transmission screen 16 by being reflected by the reflection mirror 14. Scanning light S <b> 2 indicated by a broken line that scans the lower region of the image forming range A is reflected by the second reflecting mirror 13 and the fourth reflecting mirror 15, and is reflected on the second transmissive screen 17 by the second intermediate image. Is imaged.

  The first intermediate image and the second intermediate image are formed in the image forming unit 11 by operating a movable mirror by a scanning mechanism and switching light sources of R, G, B, and the like. Various images such as numbers, characters, symbols, and the like are represented by the first intermediate image and the second intermediate image.

  As shown in FIGS. 2 and 3, a projection mirror (projection unit) 18 is provided in front of the first transmissive screen 16 and the second transmissive screen 17 in the Z2 direction. The projection mirror 18 is a concave mirror. The first transmitted light Sa including the first intermediate image transmitted through the first transmission type screen 16 is reflected and collected by the projection mirror 18, and the reflected first projection light Sv 1 is windshield glass 4. Is irradiated on the inner surface of the vehicle interior space 5 side. Similarly, the second transmitted light Sb including the second intermediate image transmitted through the second transmissive screen 17 is reflected and collected by the projection mirror 18, and the reflected second projected light Sv2 is windowed. The inner surface of the shield glass 4 on the vehicle compartment space 5 side is irradiated.

  As shown in FIGS. 2 and 3, the optical path from the first transmission screen 16 to the projection mirror 18 is longer than the optical path from the second projection screen 17 to the projection mirror 18, and as a result, The optical path from the first transmissive screen 16 to the windshield glass (projection member) 4 is longer than the optical path from the second transmissive screen 17 to the windshield glass 4.

  Further, an optical path from the image forming unit 11 to the projection mirror 18 through the first reflecting mirror 12, the third reflecting mirror 14, and the first transmission type screen 16 is changed between the image forming unit 11 and the second reflecting mirror 13. The optical path is longer than the optical path from the fourth reflection mirror 15 and the second transmission screen 17 to the projection mirror 18. That is, the optical path from the image forming unit 11 through the first transmissive screen 16 to the windshield glass 4 is longer than the optical path from the image forming unit 11 through the second transmissive screen 17 to the windshield glass 4. ing.

  As a result, the optical path from the image forming unit 11 to the first transmissive screen 16 through the first reflecting mirror 12 and the third reflecting mirror 14, and the second reflecting mirror 13 and the second reflecting mirror 13 from the image forming unit 11. The difference in optical path from the fourth reflection mirror 15 to the second transmission screen 17 can be reduced, and the two optical paths can be set to substantially the same length.

  In particular, in the in-vehicle display device 10 according to the embodiment, as shown in FIGS. 3, 4, and 6, an image formed by the image forming unit 11 includes the first reflecting mirror 12 and the second reflecting mirror 13. The scanning light S1 reflected by the first reflecting mirror 12 and the scanning light S2 reflected by the second reflecting mirror 13 interfere with each other in the different areas within the forming range A so as to face the image forming unit 11. In order to avoid this, the third reflection mirror 14 and the fourth reflection mirror 15 are disposed opposite to the first reflection mirror 12 and the second reflection mirror 13, respectively. Then, an optical path from the image forming unit 11 to the first transmissive screen 16 via the first reflecting mirror 12 and the third reflecting mirror 14, and the second reflecting mirror 13 from the image forming unit 11 The arrangement positions of the first to fourth reflection mirrors 12, 13, 14, and 15 are determined so that the optical paths from the fourth reflection mirror 15 to the second transmission screen 17 have the same length.

The display operation by the in-vehicle display device 10 is as follows.
As shown in FIG. 6, in the image forming unit 11, the display light L is scanned in the X direction, the scanning row H sequentially moves in the Y direction, and the light source is switched between them, so that the image is formed within the image forming range A. Can be formed.

  As shown in FIGS. 4 and 6, the scanning light S1 that scans the upper region of the image forming range A scans the first reflecting mirror 12, and is reflected by the third reflecting mirror 14 to be reflected by the first reflecting mirror 12. A first intermediate image is generated on the transmissive screen 16. The scanning light S2 that scans the lower region of the image forming range A scans the second reflecting mirror 13, and is further reflected by the fourth reflecting mirror 15 to the second transmissive screen 17 for the second intermediate. An image is generated.

  The transmitted light Sa transmitted through the first transmission type screen 16 is reflected and collected by the projection mirror 18, and the projected light Sv 1 is directed to the inner surface of the windshield glass 4. Similarly, the transmitted light Sb transmitted through the second transmissive screen 17 is reflected and collected by the projection mirror 18, and the projected light Sv 2 is directed to the inner surface of the windshield glass 4.

  The windshield glass 4 functions as a curved projection member, and the projection lights Sv1, Sv2 collected by the projection mirror 18 are reflected by the inner surface of the windshield glass 4, and the reflection components of the projection lights Sv1, Sv2 are reflected in the driver's seat. 7 is directed to the eyes 20a of the viewer (driver) 20 seated in the seat. As a result, the virtual images 21 and 22 formed (imaged) in the external space 6 in front of the windshield glass 4 can be viewed with the eyes 20a.

  Since the optical path from the first transmissive screen 16 to the windshield glass 4 is longer than the optical path from the second transmissive screen 17 to the windshield glass 4, the first projection screen 16 is formed on the first projection screen 16. The intermediate image is formed as a distant virtual image 21 at a position separated forward of the windshield glass 4. The second intermediate image formed on the second transmissive screen 17 is formed as a near virtual image 22 in front of the far virtual image 21 in front of the windshield glass 4.

  The viewer (driver) 20 can recognize different information at different positions by viewing the far virtual image 21 and the near virtual image 22 that are formed at different distances in front of the windshield glass 4. Become. For example, traveling information and vehicle information with high importance are displayed as the distant virtual image 21, and traveling information and vehicle information with relatively low importance are displayed as the near virtual image 22.

  In the in-vehicle display device 10, an image is formed in the image forming range A by the scanning light of the image forming unit 11. As shown in FIGS. 4 and 6, the image forming range A by the scanning light The first reflection mirror 12 and the second reflection mirror 13 occupy different areas, and the first reflection mirror 12 and the second reflection mirror 13 face the image forming unit 11. Therefore, when the image forming unit 11 scans the display light within the image forming range A, a part of the scanning light S1 can form the first intermediate image and form the far virtual image 21. A near virtual image 22 can be formed by forming a second intermediate image with the scanning light S2.

  In this way, one image forming unit 11 performs a series of scans in the X direction and the Y direction with the display light L and switches the light source to form both the far virtual image 21 and the near virtual image 22. be able to.

  In particular, when the first reflection mirror 12 and the second reflection mirror 13 are viewed from the image forming unit 11 side, the reflection mirrors 12 and 13 are not separated in the vertical direction and overlap each other by a slight dimension δ. Therefore, a useless scanning area does not occur when the display light is scanned within the image forming range A. Therefore, the far virtual image 21 and the near virtual image 22 can be formed without a time interval. The overlap dimension δ may be zero in design.

  Further, as shown in FIG. 4, the optical path from the first transmission type screen 16 to the windshield glass 4 is made longer than the optical path from the second transmission type screen 17 to the windshield glass 4, and the image forming unit The optical path from 11 to the windshield glass 4 through the first transmissive screen 16 is made longer than the optical path from the image forming section 11 to the windshield glass 4 through the second transmissive screen 17, thereby forming an image. The optical path from the part 11 to the first transmissive screen 16 and the distance from the image forming part 11 to the second transmissive screen 17 are eliminated, and the two optical paths are set to the same length.

  As a result, the first intermediate image formed on the first transmission screen 16 by the image forming unit 11 and the second transmission type by the image forming unit 11 without using an expensive optical component such as a variable focus lens. The distance between the focal points of the second intermediate image formed on the screen 17 can be made substantially the same, and the first intermediate image and the second intermediate image can be clearly formed without being out of focus.

  In the embodiment, the first transmissive screen 16 and the second transmissive screen 17 are provided to form two virtual images, a far virtual image 21 and a near virtual image 22. A third transmission type screen may be provided, and three types of virtual images may be formed at different locations in front of the windshield glass 4. In this case, the configuration is such that the three reflecting mirrors are positioned within the image forming range A shown in FIG. 6 and the three reflecting mirrors face the image forming unit 11.

A Image forming range H Scanning row L Display light S1, S2 Scanning light Sa, Sb Transmitted light Sv1, Sv2 Projection light 1 Car 4 Windshield glass 5 Car interior space 6 External space 10 In-vehicle display device 11 Image forming unit 12 First Reflective mirror 13 Second reflective mirror 14 Third reflective mirror 15 Fourth reflective mirror 16 First transmissive screen 17 Second transmissive screen 18 Projection mirror 21 Distant virtual image 22 Near virtual image 20 Viewer

Claims (4)

A first transmissive screen, a second transmissive screen, an image forming unit that forms an intermediate image on each of the transmissive screens, and a projection unit that projects the intermediate image on a projection member, In the in-vehicle display device in which the virtual image in front of the member is visible from the rear of the projection member,
The intermediate image is formed on both the first transmission screen and the second transmission screen in the common image forming unit,
The optical path from the first transmissive screen to the projection member is longer than the optical path from the second transmissive screen to the projection member,
The optical path from the image forming unit to the first transmissive screen and the optical path from the image forming unit to the second transmissive screen are substantially the same length,
An optical path from the image forming unit to the projection member through the first transmission type screen is set to be longer than an optical path from the image formation unit through the second transmission type screen to the projection member,
Virtual image based on the intermediate image formed on the first transmissive screen, characterized in that located is away from said projection member than the virtual image based on the intermediate image formed on the second transmissive screen In-vehicle display device. A first reflection mirror disposed on an optical path from the image forming unit to the first transmission type screen; and a second reflection mirror disposed on an optical path from the image formation unit to the second transmission type screen. A reflection mirror,
The in-vehicle display according to claim 1, wherein the first reflecting mirror and the second reflecting mirror are opposed to the image forming unit in different regions within an image forming range formed by the image forming unit. apparatus. The image forming unit is provided with a scanning mechanism for scanning the display light, and an intermediate image is formed on the first transmission type screen when the display light scans the first reflection mirror. The in-vehicle display device according to claim 2, wherein an intermediate image is formed on the second transmissive screen when the display light scans the second reflecting mirror. At least a part of the reflection mirror located on the optical path from the image forming unit to the first transmission type screen and the reflection mirror located on the optical path from the image formation unit to the second transmission type screen, The in-vehicle display device according to claim 2 or 3 , wherein the display device is a concave mirror.

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